1. Technical Field
The following description relates to a network system, a device forming the network system, and a program for implementing the functions of the device.
2. Related Art
In a network system including a plurality of devices (e.g. network printers) connected to a network, sharing information among the devices in the system is advantageous from various viewpoints. In a technique for such information sharing proposed in Japanese Patent Provisional Publication No. HEI11-249839, the user of the system connecting a new device to the network specifies a device that has already joined the network and the specified device transmits prescribed information to the new device, by which the device newly connected to the network acquires the prescribed information.
However, the above network system is not equipped with a mechanism for restoring the contents of the prescribed information (to be transmitted to a new device) to its original contents in case where the information is updated erroneously. Especially when the update is repeated several times, it is difficult to restore the contents of the information to the information updated several times ago.
As a mechanism for restoring the erroneous contents of the information to the original contents, it is possible to have previously save the information before update as a backup (e.g. backup file) and thereafter update the information. Specifically, in order to restore the contents of the information to those of several times ago after the update is repeated several times, each backup generated on each update of the information has to be saved and accumulated together with already-saved backups, without overwriting (updating) an old backup with a new backup on each update of the information.
However, preserving a number of backups is difficult when the capacity of a storage area for the backup information is limited. In such cases, the restoration of the contents of the prescribed information to those of several times ago (after the update is repeated several times) becomes impossible.